Zein is a family of proteins synthesized in abundance at one time during development. Consequently the nucleic acids directing their synthesis are among the most accessible for study in higher plants. The zein mRNAs can be purified nearly to homogeneity and some apparently full length cDNA clones for each of the two major classes of polypeptides have been prepared. We prepose to sequence these recombinant molecules to learn some of their important features. The cDNA clones will also be used as probes in isolating structural zein gene sequences from the maize chromosomal DNA and for mapping these sequences in the genome. Higher plants are an important group of eukaryotes for which there is currently no information on either the structure of mRNAs or the organization of structural genes. The zein genes appear to be a group of related sequences derived from a common ancestral sequence. It is expected that this study will indicate features which have been conserved as divergence occurred. Among the conserved sequences at the messenger level we expect to find the sequence involved in initiation of translation and the signal sequence at the amino terminus of the unprocessed protein. In the genomic sequences important structures to be looked for include promotor sequences and possibly those related to mRNA processing. The cloned zein structural genes can serve as important models for gene transfer studies. One of the experiments we would like to attempt is to construct a recombinant yeast plasmid vector carrying a zein structural gene to see if transcription and processing of a plant mRNA will occur in yeast. Secondly, we would like to see if a zein gene when recombined with the Agrobacterium tumefaciens Ti plasmid can be stably integrated into heterologous plant DNA.